Sharif Digital Repository

Fault tolerant operation of single-ended non-isolated DC-DC converters used in embedded and safety critical applications is mandatory to guaranty service continuity. This paper proposes a new, fast and efficient FPGA-based open and short-circuit switch fault diagnosis asssociated to fault tolerant converter topology. The results of Hardware-In-the-Loop and experimental tests are presented and discussed  

Continuity of service of wind energy conversion systems as well as their reliability and performances are some of the major concerns in this power generation area. Six-legs AC/DC/AC converters are normally used in modern wind energy systems like as in the system with a doubly-fed induction generator (DFIG). A sudden failure of the converter can lead to the total or partial loss of the control of the phase currents and can cause serious system malfunction or shutdown. Therefore, to prevent the spread of the fault to the other system components and to ensure continuity of service, fault tolerant converter topologies associated to quick and effective fault detection and compensation methods... 

The reliability of power electronic based converters has become increasingly important due to their wide-spread use in industry. An effective method to increase the availability of converters is to use condition monitoring systems for planning scheduled maintenances. This paper provides a method to monitor the condition of IGBTs in a back-to-back converter based on their on-state voltage measurement. Using the proposed system adds limited number of elements to the circuit but can be implemented independent from the converter. Considering the converter topology has made the proposed method applicable for condition monitoring of switches in different back-to-back converters. This advantage... 

Fast fault detection and reconfiguration of power converters is necessary in electrical drives to prevent further damage and to make the continuity of service possible. On the other hand, component minimized converters may provide the benefits of higher reliability and less volume and cost. In this paper, a new fault-tolerant converter topology is studied. This converter has five legs before the fault occurrence, and after fault detection the converter continues to function with four legs. A very fast fault detection and reconfiguration scheme is presented and studied. Simulations and experimental tests are performed to evaluate the structure requirements, the digital reconfigurable... 

One of the major limitations of the multilevel converters is the voltage unbalance between different levels. The techniques to balance the voltage between the different levels normally involve voltage clamping or capacitor charge and discharge control. However, traditional Flying Capacitor Converter (FCC) may be quite limited by the voltage unbalance of flying-capacitors that is the most serious problem. This paper describes operating principles of a new softswitching seven-level converter topology based on FCC for self-voltage stabilization and balancing. By adding power electronic devices to the traditional FCC topology, the proposed topology regulates the DC bus voltage and balances the... 

In this paper, application of a five-leg converter in Doubly Fed Induction Generator (DFIG) for Wind Energy Conversion Systems (WECS) is investigated. The five-leg structure and its PWM control are studied and performances are compared with the classical six-leg topology. The main drawback of five-leg converter with respect to the six-leg back-to-back converter is the need to increase the dc-link voltage for the same operation point, i.e. the same powers in case of WECS. So, different methods for the reduction of the required dc-link voltage in the five-leg case are studied. The five-leg converter is used to replace the conventional six-leg one, with the same ability. For the performance... 

Fast fault detection and converter reconfiguration is necessary for fault tolerant doubly fed induction generator (DFIG) in wind energy conversion systems (WECS) to prevent further damage and to make possible the continuity of service. Extra sensors are needed in order to detect the faults rapidly. In this paper, a very fast FPGA-based fault detection scheme is presented that minimizes the number of additional voltage sensors. A fault tolerant converter topology for this application is studied. Control and fault detection system are implemented on a single FPGA and Hardware in the Loop experiments are performed to evaluate the proposed detection scheme, the digital controller and the fault...